Instruction for installation, use and maintenance for Current and Voltage (potential) transformers
This installation, use and maintenance guide is valid for current and voltage transformers operating in outdoor or indoor conditions. These instructions are valid for Current transformer type: TPU; TPO; TP; TTR; BB; BBO; KOKS; KOFA; IHBF

1. Service conditions
Indoor transformers
The transformers should be mounted in dry indoor conditions where the ambient air is not significantly polluted by dust, smoke, corrosive gases, vapours or salt. The transformers are designed for standard ambient temperature between –5 °C and +40 °C. The altitude for use should be lower than 1000 m above the sea level. The transformers may be used also in higher or lower ambient temperatures and higher altitudes when agreed between the manufacturer and purchaser.

Outdoor transformers
The transformers should be mounted in outdoor conditions where the ambient air may be polluted by dust, smoke, corrosive cases, vapours or salt. The transformers are designed for standard ambient temperature between –40°C and +40 °C. The average value of the ambient temperature, measured over a period of 24 hours, should not exceed 35°C.

2. Technical details
The technical details for each individual transformer are mentioned on the rating plate fastened on the transformer. Values mentioned on the rating plate must not be exceeded. Markings used on the rating plate are as follows:

which is connected with earthing screw to the base plate. 7. dimensional drawings and rating plate for specific transformer type.16
.
Indoor current and voltage transformers
The mounting position of the indoor transformer can be freely chosen. When the secondary of transformer is interconnected. except if the windings of voltage transformer are connected to open delta.3. It is necessary to combine it with other technical and marketing specifications like catalogues.6. There is a M8 screw for earthing the transformer on the base plate.
Safety instructions
1. Fastening must be done on a smooth surface. The secondary like this must be additionally grounded. Where is not the national legislation requirements for competence. or near an electrical installation. 5. Protection of single pole insulated voltage transformers against feroresonance phenomena is stated in appendix 3. 6. National legislation can set down the minimum age and the criteria for competence of skilled persons working on. en 2009. with. Never short-circuit the secondary terminal of a voltage transformer even this is not in use. even if the base plate is removed. Connection between secondary terminal and base plate (ground) is shown on the picture “Crossection of double line terminal box“ 4. Always short-circuit the secondary of the current transformer. producer doesn’t warranting the earthing. The transformer is fixed using the mounting base with four screws M10 and washers.
Mounting
Following information is general and some details can differentiate according to type and variants of transformers. Residual voltage windings connected to open delta must have dn terminal earthed only on one of three transformers (earthing screws at dn terminals of others two transformers have to be removed). the criteria shall be used at least according to EN 50110-1. which is not currently in use to prevent secondary voltages which may be hazardous to personnel or damaging to the transformer’s secondary. In case of disconnection from the ground. 2. Always ground the metallic bases of instrument transformer. the grounding screw has to be removed from the secondary terminal. this is hold generally.
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1VLM000610 Rev. there should be only one grounded point to prevent accidental paralleling with system grounding wire. In case of disassembling the base plate. – Damping of the feroresonance in Voltage transformers type TJC/TJP. Connection between secondary terminal and base plate is shown on the picture “Crossection of single line terminal box“ Attention: Terminal PE must be always earthed. and do not touch the leads and terminals or other parts of the transformer unless they are known to be grounded. Always consider transformer as a part of the circuit to which it is connected. 3. A secondary short-circuit will cause the unit to overheat and fail in a very short period of time. Instruction for installation
General information
Instrument transformer is an electrical equipment and the electrical installation shall be done by skilled person only. In case of the current transformer with voltage indication (coupling electrode included) is secondary terminal box equiped with PE terminal. which must be generally earthed. Always ground one secondary terminal of the transformer.4.

Maximum allowed cantilever strength is: Voltage transformers 2000 N. Connection must be done at least on one side of the CT. Fastening must be done on a smooth surface.4. The transformer is fixed using the mounting base (VT) with four screws M10 and washers or two U profiles (CT) with M12 screws. Current transformers 5000 N. torque [Nm] M5 3. en 2009.6. The other position can be agreed with the supplier. Maximum allowed torques for screw connections of current transformers: Screw Max.5 2. there must be always connected CT shielding to the primary bar. There is a M12 screw for grounding of current transformer and M8 screw for grounding of voltage transformer. There are M12 screws used for fastening of primary conductor to the terminal.
In case of Bus CT. For primary reconnectable transformers the ratio can be reconnected by changing position of the links fixed by M8 screws without removing already fitted primary conductors.Outdoor current and voltage transformers
The mounting position of the outdoor transformer is only horizontal. One example of KOKS 12 shielding connection is described on the picture
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1VLM000610 Rev.8 M6 4 3 M8 20 16 M10 20 16 M12 70 56 Maximum allowed torque for screw connection of voltage transformer is 20 Nm.16
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Primary connection
Primary terminals of the current transformer are made of cooper and they are silver or tin plated. torque [Nm] Min.

6. en 2009. nuts and washers are made of stainless steel. Degrees of IP protection Indoor transformers: IP40. The secondary terminal cover box for indoor use is made from the plastic and provided with three detachable threaded inserts Pg16.4. The terminals are provided with M5 screws for secondary wiring connection and with through going holes for direct earthing of the secondary circuit by M5 screws.
Example of current transformers terminal boxes
TJC. or IP30 for transformers TTR.TDC TJO7 TJO6. screws. The terminal cover is seal able. The secondary cover for outdoor CT is made of epoxy resin and provided with one insert Pg21.TJC. BB.Secondary connections
The terminals.TDC
TJP.16
. KOKS Outdoor transformers: IP54 For terminal marking see appendix 1.TDO6 Example of voltage transformers terminal boxes
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1VLM000610 Rev. Secondary grounding screws and secondary terminal fastening screws are made of nickel-plated brass. The secondary cover for outdoor VT is made of plastic and provided with two insert Pg21.TDC
TJC7
TJC.

Instruction for maintenance
Excessive dust or other kind of pollution must be brushed off the transformer.
7.
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1VLM000610 Rev. Transport and storage
The permissible transport and storage temperature is from –40 °C to +70 °C. These are free of charge. Handling with the transformers
Handling with the transformer is described in the Appendix 4. en 2009. .16
. Instruction for repairing greater surface damages must be requested from the manufacturer.
6. Polluted transformers can be cleaned with spirit.
8.additional labels (if more then 2) . -
Routine test report
Together with instrument transformer are delivered: . Disposal
Materials used in instrument transformers are considered as materials without dangerous environmental impact and materials are not toxic.theoretical excitation curves There are additional extra paid reports which can be supplied on request: . During transport and storage the transformers must be protected against direct sunshine.accuracy test report . petrol or toluene. The transformers are delivered fastened to a transport pallet.magnetizing curve ( for current transformers ) . Disposal of instrument transformers is controlled by national legislation of communal waste.routine test report .4. Traces of arcs and minor surface damages can be easily removed with sandpaper after which the surface is to be treated by applying a thin layer of silicone paste on it.verification tests
5.4. Instruction for use
Current and Voltage instrument transformers are used: to convert large currents or voltage in the primary circuit to an appropriate level for secondary circuit equipment (relays and meters) .to insulate primary and secondary circuit from each other to protect the secondary equipment from the harmful effects of large current or voltage appearing during the operation (short circuits) The use of current or voltage transformer for other purpose then described above is forbidden if not agreed with the producer.two rating plates (one plastered on the transformer and one free) The following information can be included on the request.6.theoretical current/voltage errors and phase displacement values .

We cannot guarantee the value of the over-voltage factor if the requirements for the secondary winding are too high.9xUn/ 8h.4.Appendix 3.5-3) xUn/8h.6. capacitance and inductance the oscillation can be either periodic (over. Damping resistor: See the recommended value of damping resistor below:
Voltage of residual winding 100:3 V 110:3 V
Value of Rdamp 22 W 27 W
Damping power 450 W 450 W
Fig.
Damping ferroresonance for voltage transformer type TJC/TJP
TECHNICAL BACKGROUND Ferroresonance is a phenomenon usually characterized by over-voltages and very irregular wave shapes and is associated with the excitation of one or more saturable inductors through capacitance in parallel with nonlinear inductor. en 2009. can considerably reduce the risk for ferroresonance. Ferroresonance of single-pole insulated transformers in unearthed network is one of the most common ferroresonance case. Depending on the supply voltage.
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1VLM000610 Rev. There is additionally factor that can in some cases reduce or totally eliminate the risk for ferroresonance and it is over-voltage factor. shown in Fig. Higher rated over-voltage factor shift the operating point towards lower flux values of voltage transformer.1. The saturable inductor usually is present in the form of an instrument transformer. It results in smaller sensitivity of transformer to some kind of transients usually initiate ferroresonance.or sub-harmonic or with fundamental frequency) or aperiodic. According to IEC standard is the rated over-voltage factor 1. power transformer or reactor witch utilizes an iron core.16
. Using damping resistor or VT guard in the residual voltage secondary.1. RECOMMENDATION Rated voltage factor: We recommended using the voltage transformers with the over-voltage factor in the range (2.

the „switching circuit“ is switched on and current flows trough RPTC//REFI and R1. there is voltage on VT Guard terminals Uo>0. then current Uo I= flows ( RPTC // REFI ) + R1 + R 2 through the device. Basic operating states:
Simple diagram a) In case of full balance in a threephase network.16
. d) In case Uo is higher then treshold voltage(earth fault).VT Guard – function 1. Total resistance value is higher then 100ohm and voltage Uo is max 24V in this case. there is zero voltage on an open delta winding (VT Guard terminals) REFI Uo=0. VT Guard should be used in cooperation with voltage transformers connected in open delta – more in User’s manual. PTC resistor increase their resistance (The resistance is proportional to flowing current). High current flows trough the device for short time. If the Uo is lower than threshold voltage Ut (Ut =20-24V).
Important: Read the User’s manual before use. Current flowing thorough the device has very low value. b) In case of unbalance in a threephase network. Time needed for worming up PTC resistors for Uo = 100V is approximately 1. en 2009. 2. Current is limited. It is necessary to mount VT Guard in vertical position far from other thermal sources.4s. Because of low values of these resistors there is steep increase of current and fast ferroresonance dumping. No current flows through VT Guard. The device isn’t active. After earth-fault is removed.6. the PTC resistors arn’t warm up significantly. High current flows trough the device and cause to warm up PTC resistors. Because of low values of these resistors there is steep increase of current. the PTC resistors cool-down (approximately 3 min). c) In case Uo is higher then treshold voltage (ferroresonance). VT-Guard description:
VT Guard is a preventive device against the ferroresonance phenomenon which may be triggered in power networks with ungrounded or not directly grounded neutral point.4. the „switching circuit“ is switched on and current flows trough RPTC//REFI and R1.
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1VLM000610 Rev.

6. or the base of the transformer. BB(O)
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1VLM000610 Rev. Handling with transformers There are few possibilities of handling: 1) Manual handling. This system is recommended for types: TPU. Than the handling can be done by hanging of the transformer on the crane. With transformer without this handling grips is possible to grip the hooks under the base of the transformer. Transformers are possible to handle by hands in case if the weight of the transformer is not higher than 25kg. TTR. KGUG. Always use the glows in case of manual handling. Note. KOKS. Hanging systems for those types are visualized on pictures. TSR. With transformers which are equiped with handling grips is possible to handle by self-locking hooks hanging on the crane. Note. Safety warning ! Lifting capacity of the belts and the crane has to be 200kg at. TSR 3) Handling by the self-locking hooks. BB(O). TDP. For grasp of the transformers always use handling grip (see the picture). Always make sure that the hooks hold safely on the crane and on the transformer. Types TJP or TDP never handle by gripping of the fuse holder – risk of break. This handling system is vizualized on the pictures. Always make sure that the belts hold safely on the crane and on the transformer. Note: This system is recommended for types: TTR. KOKS.Appendix 4.
2) Handling by the belt Transformers where it is possible.16
. can be handling by hanging on the belts. TJC TJP. Safety warning ! Lifting capacity of the hooks and the crane has to be 200kg at least. KGUGI. TDC.4. en 2009. from safety reasons.

Safety warning! Lifting capacity of the hooks and the crane has to be 200kg at least. Never stay under the freight.6. Always make sure that the loops and chains hold safely on the transformer and chain s hold safely on the crane. TJC 7.4) Handling by the self-locking hooks under primary screws. This system is recommended for types:TPU. KOFA.16
. All transformers wich are equiped with the base plate is possible to handle by using chains and loops. KAKV.
5) Handling by the chain and loops. IHBF. TDC7. The handling can be done by hanging of the hooks on the crane. TDO. en 2009. In case of indoor current transformers. This system is recommended for most transformers with baseplate and with weight more than 40kg mainly for types: TPO.
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1VLM000610 Rev. which are equiped with primary terminal screws M12. TJP 7. Safety warning! Lifting capacity of the chains. Note.4. Note: Holding jigs. Always make sure that the freight is safely locked on the crane and make sure that there is no risk of unexpected release or turnover of the freight. described in this chapters. Note. Srew the loops (at least M10) into the baseplate and hang on the crane by chains as it is shown on the picture. are not a part of delivery. This handling system is vizualized on the picture. This handling system is vizualized on the picture.
SAFETY WARNING: During the manipulation with transformer is necessary to follow safety work instructions. TJO. there is possible to hanging the transformer on with selflocking hooks holding under primary. loops and the crane has to be 200kg at least. Always make sure that the hooks hold safely on the crane and on the transformer.

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1VLM000610 Rev. PPMV Brno Vídeňská 117 61900 Brno. en 2009. Czech Republic E-mail: info.ejf@cz.ABB s.6.abb. in the course of technical development of the product . We reserve the right to make changes of the content.o.com http://www.16
.cz/ejf
The data and ilustrations in this catalogue are not binding.abb.4.r.

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